Weeds: Blackberry (Himalayan, Evergreen, Pacific) – Rubus spp.

• Family: Rosaceae
• Cycle: Perennial
• Plant type: Broadleaf

Biology

Several species of blackberries may be considered weeds. Among these are evergreen or cutleaf blackberry (Rubus laciniatus), the native dewberry or Pacific blackberry (R. ursinus), and Himalayan blackberry (R. armeniacus, also known as R. discolor or R. procerus). Evergreen blackberry is less robust than Himalayan blackberry, with evergreen leaves that are green on both upper and lower surfaces and somewhat hairy on the undersides. The leaves are divided into pointed, sharply toothed and lobed leaflets. Stems are armed with large prickles. Dewberry has slender, trailing stems lightly armed with slender prickles. Unlike the other species mentioned here, dewberry leaves have only three leaflets. The leaflets are oval and pointed with slightly toothed margins. Himalayan blackberry is a large, aggressive plant with robust canes reaching up to nearly an inch in diameter. The canes are armed with strong, backwards-curving prickles, as are the main veins of the leaves. Leaves consist of five leaflets and are grayish on the undersides. In western Washington, leaves may persist through the winter. Long canes arch 10 feet or more over obstacles and will root to establish new plants where the cane tips contact the ground. Plants produce white to pale pink flowers in the summer, with reddish-purple to black fruits ripening in late summer. SPECIAL INFORMATION: In WASHINGTON, Himalayan blackberry (R. armeniacus) and evergreen blackberry (R. laciniatus) are designated as Class ‘C’ noxious weeds. In OREGON, Himalayan (Armenian) blackberry (R. armeniacus) is designated as a Class ‘B’ noxious weed and is also on the Oregon noxious weed quarantine list, which prohibits sale, purchase, and transport of plants, seeds, and plant parts except fruit intended for consumption. Management may be required by law in your county. Consult your local Noxious Weed Control Board for more information.

Habitat

Blackberries are found on various sites including roadsides, clearings or burned areas in woodlands, pastures, and many other areas. They are most typically a problem west of the Cascades, where they are widely established. However, they are not usually a problem in maintained lawn and turfgrass.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Cultivation (rototilling or hoeing) will effectively eliminate plants.
• Mowing to prevent seed production is a very effective means of management. In lawns, mowing regularly at the proper height for the grass species may help minimize weed growth and invasion.
• Careful digging is useful to manage weed populations. However, digging can carry undesirable weed seed to the surface and foster further germination.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Apply glyphosate products in September to October when canes still have foliage and after berries are formed.
• Fall treatment must be made before a killing frost.
• Triclopyr products are effective and are available for non-specific area application.
• Glyphosate products should be applied as spot treatments only!
• Herbicides should be used with caution if the fruit may be eaten.
• NOTE: Some ingredients listed here are only available in combination.
• Read the label carefully on combination products to make sure the product is suitable for your specific situation.

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